Vacuum cleaners, such as upright vacuums, remove dirt from a carpet by creating a suction strong enough to draw the dirt particles from a section of the carpet up into the vacuum cleaner where the dirty air is passed through a vacuum bag in which the entrained dirt is captured. To increase the efficiency of this process, a base portion of the vacuum cleaner often has a roller brush for agitating dirt from the carpet as it is being vacuumed.
Inside the vacuum cleaner, a dirty air conduit transfers the dirty air from the base of the vacuum cleaner to the vacuum bag. The dirty air conduit runs up a handle assembly or, in cases where the dirty air conduit is rigid, the dirty air conduit can itself function as a portion of the handle. At the end of the dirty air conduit opposite the floor there is a dirty air outlet nozzle where the dirty air exits from the dirty air conduit. The vacuum bag is attached to the dirty air outlet nozzle.
The vacuum bag has a bag opening that fits closely over the dirty air outlet nozzle. The vacuum bag is otherwise a completely closed bag that is made from a porous material that allows air to flow through it, but which is too fine for most dirt particles to pass through. As dirty air passes through the vacuum bag, the air is forced through the porous material and the dirt is trapped in the bag. The bag thus collects the dirt from the dirty air and, more importantly, from the floor. Because the material of the vacuum bag is often fragile and can get very dusty, the vacuum bag is commonly held within a protective outer bag.
The outer bag is typically placed over the dirty air outlet nozzle first, with the dirty air outlet nozzle extending through a hole in the outer bag. A clip is then placed over the dirty air outlet nozzle between the outer bag and a protrusion on the outer surface of the dirty air outlet nozzle. The clip retains the outer bag in the proper position for use. Finally, the vacuum bag is placed over the remaining length of the dirty air outlet nozzle, and the outer bag closed.
To eliminate the need for emptying or cleaning the vacuum bag after it has collected dirt, vacuum bags have been modified over the years to be disposable. This allows the user to merely discard the dirty vacuum bag and replace it with a new, clean one. To adapt the vacuum bags for easy replacement, the bags have been designed so that the bag opening can be releasably engaged with the dirty air outlet nozzle.
One common vacuum bag design incorporates a reinforced area, known as a collar, surrounding the bag opening. The collar is usually a square or rectangular piece of thin cardboard. To install the vacuum bag, the user holds the collar by one or more edges, and forces the bag opening over the dirty air outlet nozzle. The collar can be designed with an elastic seal extending inward from the circumference of the bag opening to further seal the gap between the dirty air outlet nozzle and the bag opening.
Typically, installation of a vacuum bag is done by hand. A user inserts the vacuum bag into the outer bag, aligns the vacuum bag opening with the dirty air outlet nozzle and pushes the vacuum bag onto the nozzle. The installation of the vacuum bag by hand has obvious drawbacks including misalignment and an incomplete connection of the bag with the dirty air outlet nozzle.
An improperly installed vacuum bag can become damaged and is more likely to leak or disengage during use.
In an attempt to solve the problems of both alignment and retention, some vacuum cleaners come equipped with a bag docking assembly. Examples of bag docking assemblies are discussed in U.S. Pat. No. 5,089,038 to Kopka et al., U.S. Pat. No. 5,444,385 to Jailor et al. and U.S. Pat. No. 6,033,451 to Fish et al. Kopko et al. describes a docking system comprising a rigid housing surrounding both the vacuum bag and dirty air outlet. A hinge is integrally formed on the inside of the housing. A mounting plate holding the vacuum bag by its collar is attached to the hinge, and pivots to engage and disengage the vacuum bag from the dirty air outlet nozzle. When the mounting plate is rotated to the point of engagement, the collar on the vacuum bag seals with the dirty air outlet nozzle. When the mounting plate is rotated to the point of disengagement, a user accessing the unit from the back of the housing may remove the vacuum bag from the mounting plate and replace it with a new one.
The Fish et al. invention describes a docking system with a separate anchor and mounting member. The anchor member attaches to the dirty air outlet and is connected to the mounting member via a hinged portion. The mounting member has side walls that allow for engagement of a bag collar. When placing a vacuum bag into the docking assembly the mounting member is rotated to an open position and the vacuum bag collar is inserted into the mounting member so that the edges of the vacuum bag collar line up with the side walls. Once the vacuum bag is inserted in to the mounting member the mounting member is rotated back into contact with the anchor member.
Although the docking assemblies described are an improvement over manual placement of a vacuum bag into a vacuum, the current state of the art still exhibits problems with alignment and retention. In the prior art described, it is possible to insert the vacuum bag in orientations that were not intended by the dock manufacture. For example, it is possible for a user to insert a vacuum bag upside down or only partially, thus leaving gaps for the escape of unfiltered air or damaging the vacuum bag when the docking assembly is closed.
In addition to problems with alignment and retention, the prior art docking assemblies lack ease-of-use features that enable customers to easily replace a vacuum bag. In Fish et al., the mounting member can pivot freely, causing the vacuum bag to be compressed against vacuum forcing air and dirt out of the opening in the bag collar before the opening can be closed. Also, when attempting to remove the vacuum bag from the docking assembly it is difficult to grab hold of the bag because the top of the bag collar and the top edge of the docking assembly are at the same height leaving little space in which to grab hold of the collar. Additionally, it is difficult to insert the bag collar into the docking assembly. The docking assembly has a very narrow opening for inserting the vacuum bag collar, necessitating careful alignment when sliding the vacuum bag collar into the docking station.
A need therefore exists for an improved bag docking assembly for aligning a vacuum bag with a dirty air outlet nozzle, and for retaining the vacuum bag in the position of engagement.